1. Field of the Invention
The invention relates in general to a TV information system and data receiving method, and more particularly to a VBI receiver and the related method.
2. Description of the Related Art
In a TV information system, data of climate, news, stock markets, and programs, after digitally encoded, are packed in the vertical blanking interval (VBI) of a TV signal, and then broadcasted via a wireless or cable TV station. This kind of TV information is ordinarily called VBI data. The TV information receiver at the receiving terminal receives the TV broadcast signal, catches the encoded data string from the VBI, and decodes the data string to recover the original data content. Afterward, the information service contents can be selected or inquired via a remote control as needed.
FIG. 1 is a block diagram of a conventional TV information decoding system. The TV information decoding system includes a front-end circuit 110, a VBI decoder 120 and a TV decoder 130. ATV broadcast signal received though an antenna is demodulated to be a baseband video signal by the front-end circuit 110, while the baseband video signal is decoded to become VBI data by the VBI decoder 120. Afterwards, the VBI data output by the VBI decoder 120 is received and transmitted to a mixer 134 by the VBI receiver 133, where the VBI data is combined with the video information to be displayed on a TV monitor. However, when the VBI data are transmitted to the TV decoder 130 by the VBI decoder 120, only the signal Vsync is served as field synchronization mechanism and the signal Hsync as linear synchronization mechanism between the VBI decoder 120 and the TV decoder 130. Therefore, the accuracy of VBI data received by the VBI receiver 133 of the TV decoder 130 requires further improvement.